Distinguish spoiler-flagged images

As a mod, I appreciate the ability to turn off spoilers.  However, there are cases where I want to require spoiler tagging.  To enforce this, I have to know what is tagged as a spoiler.  For text, this isn't a problem--even if spoilers are turned off, the styling makes it obvious.  However, for attached files, there's no equivalent.  I have to either turn spoilers back on or grab the image link and inspect the filename.  These are clunky workarounds.  I would like some sort of clear indicator so I can see at a glance if an uploaded image is tagged as a spoiler or not.  I would settle for an indicator in the lightbox so it's at least never *more* work than having spoilers enabled.